06-23-2009 06:56 PM - edited 03-06-2019 06:25 AM
I have known that each IP have only another MAC address number.
But actuality, another result appears on the router when I enter commend " show arp | includ 001a.2f85.4abf ".
Please refer to below logs.
Router#show arp | include 001a.2f85.4abf
Internet 12.53.117.1 - 001a.2f85.4abf ARPA GigabitEthernet3/15
Internet 12.53.117.17 - 001a.2f85.4abf ARPA GigabitEthernet3/16
Internet 12.53.180.2 - 001a.2f85.4abf ARPA Vlan180
Internet 12.52.227.1 - 001a.2f85.4abf ARPA GigabitEthernet6/1
Internet 12.52.228.2 - 001a.2f85.4abf ARPA GigabitEthernet6/2
Internet 12.53.198.2 - 001a.2f85.4abf ARPA Vlan198
LN13P_SW2#sh mod
Chassis Type : WS-C4507R
Power consumed by backplane : 40 Watts
Mod Ports Card Type Model Serial No.
---+-----+--------------------------------------+------------------+-----------
1 2 Supervisor IV 1000BaseX (GBIC) WS-X4515 JAE1052J01A
2 2 Supervisor IV 1000BaseX (GBIC) WS-X4515 JAE1137WQW8
3 18 1000BaseX (GBIC) WS-X4418-GB JAE11054626
4 6 1000BaseX (GBIC) WS-X4306-GB JAE1135V6DK
5 6 1000BaseX (GBIC) WS-X4306-GB JAE0918BF1H
6 6 1000BaseX (GBIC) WS-X4306-GB JAE1046F7P8
7 48 10/100BaseTX (RJ45) WS-X4148-RJ JAE1044EE6C
M MAC addresses Hw Fw Sw Status
--+--------------------------------+---+------------+----------------+---------
1 001a.2f85.4a80 to 001a.2f85.4a81 5.2 12.2(20r)EW1 12.2(31)SGA8 Ok
2 001a.2f85.4a82 to 001a.2f85.4a83 5.4 12.2(20r)EW1 12.2(31)SGA8 Ok
3 0014.1cbe.0d8e to 0014.1cbe.0d9f 1.3 Ok
4 0018.7380.46ea to 0018.7380.46ef 4.3 Ok
5 0013.1ac9.1ff0 to 0013.1ac9.1ff5 4.0 Ok
6 0019.e8dc.4250 to 0019.e8dc.4255 4.2 Ok
7 0019.e788.9630 to 0019.e788.965f 3.3 Ok
Mod Redundancy role Operating mode Redundancy status
----+-------------------+-------------------+----------------------------------
1 Active Supervisor SSO Active
2 Standby Supervisor SSO Standby hot
What is the "001a.2f85.4abf" ?
06-23-2009 11:17 PM
Hello Kwangwon,
what you see is normal this is a multilayer switch 4500.
in this kind of devices all L3 interfaces use the same MAC address unless explicitly configured.
001a.2f85.4abf is a MAC address in the MAC address range of the active Supervisor as you can see from this line:
1 001a.2f85.4a80 to 001a.2f85.4a81 5.2 12.2(20r)EW1 12.2(31)SGA8 Ok
a different source MAC address taken from the range is used on L2 port for sending CDP messages , STP BDPUs and so on
Hope to help
Giuseppe
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